Field of the Invention
The present invention relates to an imaging lens that is particularly suitable for use with electronic cameras, and an imaging apparatus provided with the imaging lens.
Description of the Related Art
In recent years, many digital cameras provided with a large image sensor conforming to the APS format or the Four Thirds format, for example, are launched into the market. Also, besides digital single-lens reflex cameras, lens-interchangeable digital cameras and compact cameras which use the above-described large image sensor and are not provided with a reflex finder are recently launched into the market. Advantages of such cameras lie in that they have a compact entire system and are highly portable, while achieving high image quality. Along with the more and more compact design of cameras, there are increasing demands for a lens system having a small entire length.
Examples of a large-aperture imaging lens having an f-number of around F1.4 while being usable with the above-described large image sensor have been proposed, for example, in Japanese Unexamined Patent Publication No. 2011-158739, and International Patent Publication No. WO2011/108428 (hereinafter, Patent Documents 1 and 2, respectively). In both the imaging lenses disclosed in Patent Documents 1 to 2, a strong concave surface toward the object side is disposed on the image side of the stop to thereby achieve a lens configuration that provides a long flange back (or flange focal length).